Considerations on neurotrophic relations in the central and peripheral nervous system

Abstract

The evidence for the existence of neurotrophic (non-impulse) influences is reviewed especially with respect to choice of adequate parameters and of differentiation of neurotrophic influences from other mechanisms affecting intercellular relations. The importance of growth processes in neurotrophic control is stressed, the mechanisms being apparently similar in the central and peripheral nervous system. Collateral sprouting as a compensatory response of the neuron on one hand and the old age changes at neuromuscular synapses resulting in "silent" synapses and later "silent" terminals present phenomena indicating mechanisms of growth and arrest of growth processes in neurotrophic control.